This paper aims, probably as the first academic attempt, to search for a Common Law in East Asian legal history. The concept of Common Law in the Western legal history also is rather complicate and ambiguous. There was a previous concept; ius commune or gemeines Recht in the continental Europe, meaning the roman law used commonly in the whole European territory(usus modernus pandectarum). The concept of common law used in this paper is rather similar to the continental-European ius commune. This writer tries to dig out the common law in East Asian legal history, particularly on the following four grounds: